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Novel method to quantify traction in a vitrectomy procedure
  1. Anderson Teixeira1,3,4,5,
  2. Lawrence Chong2,
  3. Naoki Matsuoka1,4,6,
  4. Adrian Rowley1,4,
  5. Jaw-Chyng Lue1,
  6. Matthew McCormick1,
  7. Ralph Kerns1,
  8. Mark Humayun1,3,4,5,7
  1. 1Eye Concepts, Los Angeles, California, USA
  2. 2VMR Institute, Huntington Beach, CA, USA
  3. 3Doheny Retina Institute, Los Angeles, California, USA
  4. 4Doheny Eye Institute, Los Angeles, California, USA
  5. 5Department of Ophthalmology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
  6. 6Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Science, Niigata University, Niigata, Japan
  7. 7Department of Biomedical Engineering, Viterbi School of Engineering of the University of Southern California
  1. Correspondence to Dr Mark Humayun, Eye Concepts Laboratory, Doheny Eye Institute, 1450 San Pablo Street DEI 1900, Los Angeles, CA 90033-4500, USA; mhumayun{at}


Aim To report a novel method to quantify traction applied to the retina using vitreous cutters during pars plana vitrectomy.

Methods Fresh porcine eyes were positioned in a specially developed holder and transfixed to the retinal layers with a wire and the other end fixed to the load cell of a strain gauge. Five separate 20-gauge electrical drive mechanism vitrectors were introduced into the eye at a 45° angle and positioned at a distance of either 3 or 5 mm from the retina. Data from the strain gauge were acquired and the traction force computed.

Results The analysis revealed that the vitreoretinal traction increased by 7.90 dynes for each 100 mm Hg increase in vacuum (p<0.05). The traction forces decreased by 2.51 dynes for each 500 cuts per minute increased (p<0.05) and the traction force increased by 2.17 dynes at 3 mm compared with 5 mm (p<0.05).

Conclusion The traction was directly proportional to the aspiration vacuum and inversely proportional to the cut rate. The cutter traction force increased with proximity to the retina.

  • Experimental and laboratory
  • retina
  • treatment surgery
  • vitreous

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  • Funding This study is supported by Eye Concepts at the Doheny Eye Institute. Eye Concepts receives research funds that are part of an advanced royalty distribution agreement between Bausch & Lomb Inc, Rochester, NY and the Doheny Eye Institute. The sponsor organisation had no role in the design or conduct of this research.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.